Device at lock

ABSTRACT

The present invention relates to an arrangement for a lock ( 2 ) for doors ( 3 ).  
     An electromechanical unit ( 6 ), with an integral electrically driven stepping motor ( 7 ), which is intended to operate the lock handle by actuation of the motor ( 7 ), is capable of being applied to the inside ( 3 A) of the door ( 3 ).  
     An electronic unit, which is capable of being actuated by an electronic key, is capable of being mounted on the outside of the door ( 3 ), which unit is so arranged as to interact with a magnetic field with a predetermined frequency and by wireless communication between the key and the unit.  
     A power supply unit is provided, and a central processor unit is so arranged as to monitor the aforementioned electromechanical unit ( 6 ) and an RFID reader contained in the electronic unit.  
     Arranged between the motor ( 7 ) and the lock ( 2 ) is a rotating driver ( 13 ) for transferring the force from the motor ( 7 ) to the lock ( 2 ).

The present invention relates to an arrangement for sensing the positionof the lock bolt in a lock intended for the door to an apartment, forexample, which lock comprises an internal lock handle, a lock bolt, adriver arranged between a motor and the lock for the transfer of forcefrom the motor to the lock and a number of gear wheels.

Previously disclosed are motorized locks, for example for doors, whichare so arranged as to be caused respectively to be locked and unlockedwith the help of contactless electronic keys, for example tags, whichare in communication with a lock control centre, in which an RFID readeris included.

The method of sensing the position of a lock bolt with the help of oneor more Hall elements is already familiar. In previously disclosedarrangements, these sensors are placed directly adjacent to the lockmechanism, either inside the lock casing by the manufacturer of the lockor externally in the striking plate on the door frame, which requiresthe routing of cables between the door frame and the control system. Itis customary in the automobile industry to use arrangements which makeuse of magnets and Hall elements in order to sense the position in whichthe ignition key is situated.

Described in U.S. Pat. No. 6,223,571 B1, for example, is a system whichsenses a number of predetermined positions between its Hall elements anda magnet and acts directly in response to this, for example by startingan engine. It functions quite simply as a mechanical switch with fixedpositions, for which it acts as a functional replacement. See also U.S.Pat. No. 6,067,824 A, which relates to a similar system.

Described in U.S. Pat. No. 5,890,384 A and WO 01/00462 A1 arearrangements which use Hall elements in order to sense the position ofthe lock bolt in a vehicle door.

The purpose of the arrangement in U.S. Pat. No. 5,862,691 A is to ensurethat the predetermined positions in a lock with Hall elements cannot bemanipulated from outside with a powerful magnet. The function isotherwise similar to that described in U.S. Pat. No. 6,223,571 B1, thatis to say it directly replaces the function of a mechanical switch withpredetermined fixed positions.

In all the above-mentioned documents, sensing takes place directly,regardless of whether it is concerned with determining the position ofthe ignition key or the position of the lock bolt.

An RFID reader is constituted by an electronic unit, the purpose ofwhich is to generate a magnetic field with a specific frequency, whichin turn is capable of inductively activating an electronic key in ordersubsequently to establish wireless communication between them.Communication is only possible when the key is present in the magneticfield. However, the lock and the associated inspection and control meansare designed and constructed to function solely as a so-called motorizedlock. This means that it is necessary to replace existing locks, insteadof being able to convert the lock to enable it to function as aso-called motorized lock, which is controlled by keyless influence. Forall types of motorized lock, it is necessary for the position of thelock bolt to be known at all times by the control electronics. This isparticularly important in order to be able to establish whether or notthe lock has actually locked.

The principal object of the present invention is, in relation to anarrangement of the above-mentioned kind, indirectly to detect theposition of a lock bolt, which does not necessarily correspond directlyto a given position between the Hall elements and the magnet. Indirectsensing in this case means: sensing of a mechanical position (the lockbolt) in a closed system (the lock casing in the door) other than thesystem which records the sensing (the lock motor), and that the sensingis not performed directly on the part that is the object of the sensing(the lock bolt).

The aforementioned object is achieved by means of an arrangement inaccordance with the present invention, which is characterizedessentially in that a number of sensors is attached adjacent to one ofthe gear wheels for detecting the position of the lock bolt.

The invention is described below as a number of preferred illustrativeembodiments with reference to the accompanying drawings, in which

FIG. 1 shows a lock on a door viewed from outside and shown partly as anexploded view;

FIG. 2 shows the lock viewed from the inside of the door and with thecover panel removed;

FIG. 3 shows a perspective view of an electromechanical unit included inthe arrangement;

FIG. 4 shows a plan view of parts included in the aforementioned unit;

FIG. 5 shows the lock and the unit viewed at an angle from the outeredge of the door;

FIG. 6 shows a door and a lock viewed from outside;

FIG. 7 shows a handle and a driver and their associated fixing screws;

FIG. 8 shows the handle in the installed position;

FIG. 9 shows the positions of the sensors in relation to the magnet,viewed from above; and

FIG. 10 shows a lock motor, without its cover and without the normaldoor handle, mounted on a door.

The invention relates to an arrangement 1, which is intended to becapable of connection to existing, pre-installed or other standard locks2, and which is intended for an apartment door 3, for example,comprising an internal lock handle 4 and a lock bolt 5.

In accordance with the invention, an electromechanical unit 6, whichcomprises an integral electrically driven stepping motor 7, which isintended to actuate the lock handle 4 under the influence of the motor7, is capable of being applied to the inside 3A of the door 3, forexample as shown in FIG. 5.

An electronic unit 8, which is capable of being actuated by anelectronic key, is capable of being mounted on the outside 3B of thedoor 3. The aforementioned unit 8 is so arranged as to interact with amagnetic field, which exhibits a particular frequency, and by wirelesscommunication between a key (not shown here) and the aforementioned unit8. A power supply unit is also provided as well as a central processorunit (not shown), which is so arranged as to monitor the aforementionedelectromechanical unit 6, and an RFID reader contained in the electronicunit 8. Arranged between the motor 7 and the lock 2 is a rotating driver13 for transferring the force from the motor 7 to the lock.

Described below in greater detail is an electromechanical unit with anintegral motor intended to actuate the lock handle, for example in anapartment door, on an existing standard apartment lock, for example ofthe type ASSA 8765.

The purpose of the whole arrangement is to obtain the function of acomplete motorized lock by simple and inexpensive means, whereby theaforementioned unit provides the electromechanical control and theexisting lock provides the actual lock mechanism, and to be able tosense whether the door 3 is fully closed and whether the lock bolt 5 isin the retracted or extended position. No modification is required tothe existing lock. The only necessary addition to the lock is a longerdriver and two longer fixing screws. The unit is mounted on the insideof the door between the lock handle of the existing lock and the dooritself. The existing lock handle is mounted on top of the unit with thehelp of the extended fixing screws.

The motorized lock described above is intended to be included in asystem, which is under the overall control of a central unit known asthe central processor unit. Important constituent parts of the system,apart from the motorized lock and the central processor unit, are anRFID reader (reader) and a power supply unit. The purpose of the entiresystem is to avoid the need to use keys for the apartment doors. Insteadof a key, a contactless electronic “key” (tag) is used containing aunique code, which is read by the RFID reader when the owner holds his“key” in front of the reader. The RFID reader can be screwed securely tothe outside of the door directly over the lock.

The electromechanical unit 6 comprises a number of gear wheels 10, 11,12, of which one gear wheel 12 accommodates a central part 13A of adriver 13 executed as a flat rotating shaft in an elongated hole 14. Theaforementioned electromechanical unit 6 is accommodated by a bottomplate 40 made of metal capable of being attached to the door 3 and witha protective enclosure made of metal (not shown) over the parts that arepresent thereon.

The aforementioned manually actuated lock handle 4 is attached to thedriver 13, more particularly to its free end 13B, and the aforementionedbottom plate 40.

The power transmission consists of three gear wheels 10-12 contained ina gearbox in order to obtain the necessary force to cause the driver 13of the lock to rotate. Belt pulleys, for example, can be used in placeof gear wheels. The first gear wheel 10 sits on the motor shaft. Anintermediate gear wheel 11 is provided in order to obtain a sufficientdistance between the motor and the driver. The last gear wheel 12 has atranscurrent rectangular hole 14, through which the driver 13 isinserted in conjunction with assembly of the unit 6 on the door 3 and inthis way will cause the driver 13 to rotate when the motor 7 isactivated. The last gear wheel 12 is glued in a bearing 9 (ball bearing)to enable it to be caused to rotate. The ball bearing 9 is attached tothe bottom plate 40 in the enclosure.

The gear reduction achieved by the gear wheels 10-12 is selected so thatsufficient force is available at the last gear wheel 12 without at thesame time there being excessive inertia for the whole assembly to berotated backwards with the help of the lock handle 4 when the lock 2 isactuated manually. The total gear reduction is six fold.

Small high-speed servomotors with a screwed-on gearbox are used in aconventional motorized lock. This arrangement has two weaknesses, whichare neutralized in the present unit 6. A high gear reduction, of theorder of 50-100 fold, is required because of the high speed of themotor, which results in the need for small mechanical dimensions inorder to be able to accommodate everything in a very limited space. Thefirst weakness is that the gearbox with its associated motor isexpensive. The second is that the small dimensions of the gearbox meanthat it is mechanically fragile by necessity, which is manifested whenthe bolt of the lock makes abrupt contact with, for example, thestriking plate of the door frame in the event of a failed attempt atlocking. Special mechanical solutions must be used in order to mitigatethe effect of the strong forces that arise inside the gearbox inconjunction with such highly abrupt deceleration. The high gearreduction also means that problems with very high speeds of rotationoccur in the motor, since the whole assembly must be rotated backwardswhen the lock handle is rotated manually.

The motor 7 in the present unit 6 is preferably a stepping motor. Thishas the advantage of being inexpensive, and it lends itself to speedcontrol in a very direct fashion without the need for an expensive andmechanically fragile gear reduction. This type of motor has acharacteristic feature which is very often regarded as negative, butwhich is turned to an advantage in this case. When the motor encountersexcessive resistance, it loses its turning moment monetarily andinstantaneously, which means that it can no longer transmit anydestructive force. It is precisely this characteristic that is sought inthe event of such a highly abrupt stop.

Thanks to the direct speed control of the stepping motor and itsrelatively high underlying torque, only a relatively modest gearreduction of a given basic speed is required in order to obtain thenecessary force. The gear reduction in its entirety can accordingly bemade compact and with suitably dimensioned gear wheels and shafts whichare able to withstand the forces generated by abrupt deceleration.

Holes 44 for the fixing screws of the RFID reader are also shown in FIG.1, and the two fixing screws 41 for the handle and a fixing screws 42for the motor are shown in FIG. 3. Holes 43 for fixing the plate 40 withscrews are also shown in FIG. 3. Fixing screws 45 for the attachment ofthe RFID reader are also shown in FIG. 6.

An electronic connection is required in order to be able to control themotor 7, read the sensors, receive commands to activate the motor 7, andreport the status of the lock. This electronic connection is positionedinside the same enclosure as the motor 7 and the power transmission. Theelectronics communicate directly with the central processor unit andonly activate the motor control once the central processor unit hasapproved this.

Sensors or transducers are required in order to be able to establishwhether the door 3 is fully closed and whether the lock bolt 5 is fullyextended from or fully retracted into the lock. The unit 6 must onlyactivate the motor 7 when the door 3 is fully closed. A magnetic contactpositioned in the door frame is used for this purpose.

In order to be able to determine electronically whether the lock bolt ina door lock is locked or unlocked, some form of sensor/transducer isrequired which is capable of reading the position of the lock boltdirectly or indirectly, that is to say whether it is in a retractedposition (unlocked) or in an extended position (locked).

An entirely new arrangement must be developed in order for this to befeasible in a simple fashion without having either to modify thestandard lock or to position external sensors. This arrangement, seeFIGS. 9 and 10, functions by indirectly sensing the position of the lockbolt 5 with the help of a number of sensors H1, H2, H3, H4 and a magnet51, and is described below. The aforementioned sensors preferablyconsist of Hall elements.

FIG. 9 shows the positions of the Hall elements H1-H4 in relation to themagnet 51, viewed from above. The Hall elements H1-H4 together with allthe other necessary electronics are mounted on a circuit board 50. Thecircuit board 50 is permanently mounted on a bottom plate 40. The bottomplate 40 is mounted on the door 3 on which the lock motor will bemounted. The magnet 51 is mounted on the gear wheel 12 which causes thedriver 13 to rotate.

FIG. 10 shows the lock motor, without its cover and without the standarddoor handle, mounted on a door 3, all viewed from the side. Note thatthe driver 13 is not included in the lock motor. It is a separatestandard component that is connected between the lock motor and the lockin the door.

The motor 7 that is present inside the enclosure in the arrangementactuates the driver 13 of the lock via a number of gear wheels 10-12. Asmall magnet 51 is located on the gear wheel 12 that is in directcontact with the driver. The location of the magnet 51 can also beeffected on, for example, the driver 3 or one of the other gear wheels10, 11. The selected gear wheel 12 represents the optimal solution inthis context, however. When the driver 13 is caused to rotate, either bymanual actuation or by being actuated by the motor 7, the magnet 51 willalso be caused to rotate because the gear wheel 12 is always in directcontact with the driver 13. The driver 13 is, in actual fact, a looselyconnected shaft which passes all the way through the gear wheel 12. If anumber of Hall elements H1-H4 is placed directly above the envisagedpath of the magnet 51 and at strategic points, for example, the Hallelements H1-H4 can indicate the positions on the rotating path of thedriver 13 which correspond to the reversal positions of the lock bolt 5.Since the sole function of the driver 13 is to transmit a rotating forcein order to be able respectively to lock and unlock the lock in the door3, it is thus possible by this indirect means to sense the position ofthe lock bolt 5, i.e. whether the lock is unlocked or locked.

Sensing is used in the arrangement in order to sense the position inwhich the lock bolt 5 finds itself on the one hand in an indirectfashion and, on the other hand, to determine whether the lock is subjectto inertia (“inertia sensing”) or if the lock bolt 5 has jammed. Sensingalso functions as a safety mechanism to prevent the activated motor 7from remaining activated for an excessively long period when the lockbolt 5 has become jammed, and it also tells the control electronics whenthe right lock bolt position has been reached when actuation of the lockbolt 5 is effected with the help of the motor 7. In order to be able todetermine the position of the lock bolt 5 when the handle on the lock isactuated manually, all the Hall elements H1-H4 are read continuously. Inthis way, the control electronics are aware at all times whether thelock is locked or unlocked, regardless of whether the lock bolt has beenactuated manually or with the help of the lock motor 7 (motor control).The entire procedure takes place in such a way that no external sensorsare required in order to detect the position of the lock bolt 5. All theHall elements H1-H4 are positioned inside the same enclosure that isconstituted by the lock motor 7. No modification is required to theexisting lock for all of this to function as described above.

Hall elements H1 and H4 are used for motor control, and H2 and H3 areused to sense the position of the lock bolt in conjunction with manuallocking/unlocking.

A computer program for controlling the control electronics must alwaysbe installed; this uses one or more algorithms to enable it finally todetermine the position of the lock bolt. Rotation of the driver can, infact, be executed so that the magnet moves past the respective Hallelement, but without the lock bolt having changed its position for thatreason. It is thus not possible to state that a given Hall elementcorresponds to an exact position for the lock bolt.

All the Hall elements are used for sensing in conjunction with “inertiasensing”.

The motor 7 causes the driver 13 of the lock to rotate with the help ofthe gear wheel 12. The driver passes through the elongated hole 14 inthe gear wheel. The driver in turn causes a mechanism in the lock casingto rotate, which finally causes the lock bolt 5 of the lock to move. Inorder to be able to determine the position of the lock bolt 5 withouthaving any form of external sensor, a magnet 51 is used which is mountedon a gear wheel 12. The position of the magnet 51 is determined by theHall elements H1-H4 that are located on the circuit board 50 of the lockmotor. The circuit board 50 contains all the necessary electronics forreading the Hall elements H1-H4 and controlling the motor 7. A total offour Hall elements is preferably used for position sensing and “inertiasensing”. The reason why four Hall elements are required rather than twois because this gives greater reliability in conjunction with motorizedlocking. This in turn derives from the fact that, in conjunction withmanual rotation, the handle is rotated until the lock bolt reverses andthe user hears this and accordingly stops rotating the handle. Thisgives rise to two reversal positions, which are situated relativelyclose to one another. When account is taken of various mechanicaltolerances in the lock, carelessness in the assembly of the lock motorand scatter in the detection range of the Hall elements, it will beappreciated that the above-mentioned reversal positions cannot be usedin conjunction with motorized locking, since the various positions canbe reached without the lock bolt having locked or unlocked for thatreason. Sensors are required, therefore, which cause the lock motor torotate the driver past the respective manual reversal positions. Themanual positions must be retained, however, because a user who rotatesthe handle manually will still only rotate the handle precisely to thepoint at which the lock bolt reverses.

The Hall elements H1-H4 must not necessarily be mounted on a circuitboard 50 above the magnet 51. They can be mounted in a different way,although they must still be mounted sufficiently close to the magnet topermit sensing to take place. In order for the whole to function, someform of control electronics with an associated computer program must beprovided. These control electronics can be contained with advantage inthe same enclosure as the mechanical parts, although this is notessential.

“Inertia sensing” is one means by which the control electronics in thelock motor can determine the time taken respectively to lock and unlockthe lock. This is done by sensing the time taken to rotate the magnetfrom one Hall element with a given position to the next one. Differenttime criteria must be met during the actual motorized locking procedure.These criteria are dependent on the position that is the starting point.Failure to meet certain of the criteria will stop the motor, and anumber of repeated attempts to lock or unlock will be initiated. Ifother criteria are not met, which mean that the lock is locked orunlocked, but if it takes too long to do this, this will be reported toa host system, which in turn will store the incident in its memory.These incidents can then be read by a user at a central level and, forexample, they can serve as the basis for remedial adjustments to thearrangements that exhibit problems.

In order respectively to lock and unlock a lock of the type ASSA 8765manually, for example, it is necessary for the carrier to be rotatedthrough ca 100 degrees from a given locked or unlocked position to theopposite position. For the purpose of motor control, the rotation mustbe greater in order to be able to guarantee that the lock has reallychanged status from locked/unlocked to the opposite status. In this casea rotation of ca 180 degrees is considered to be sufficient. Types oflock other than ASSA 8765, for example, may require different positionsfor the Hall elements in order to sense the reversal positions, althoughthe method remains the same.

In both cases, it is necessary to cause the driver to rotate until thelock bolt of the lock has changed its position either from fully lockedto fully unlocked, or vice versa. A 180-degree rotation of the driver isnot normally executed in the case of manual rotation, as this is notnecessary—the person who rotates the handle rotates it only until thelock bolt has changed position, since audible feedback occurs onreversal.

It should be possible to utilize this feedback in an envisagedapplication by using a microphone as a sound recording device and bythis means being able to identify the reversal between a fully unlockedlock and a fully locked lock. This method nevertheless suffers from thedisadvantage that it is easy to disrupt, for example, if someonemistakenly pulls at the door at the same time as the lock is in theprocess of locking.

It is thus necessary in the case of manual rotation for the driver to becaused to rotate via the handle that is mounted on the enclosure of thelock motor, in such a way that H1 and H4 will very often not be able tosense the position of the magnet. In order to be able to determine theposition of the lock bolt in conjunction with manual rotation, a furthertwo Hall elements must be used. These are designated as H2 and H3 inFIGS. 9 and 10. H2 and H3 are positioned in such a way that, inconjunction with manual rotation, they indicate the position of the lockbolt with the lock bolt out (locked lock) or with the lock bolt in (lockunlocked).

Since mechanical tolerances, carelessness in assembly and even scatterin the detection range of the Hall elements must not be allowed toinfluence security, in particular in conjunction with locking with thehelp of motorized control, Hall elements H1 and H4 must be used inconjunction with motorized control. If only Hall elements H2 and H3 wereto be used, it would not be possible with any certainty to determine,for example, the correct position of a locked lock bolt, for the simplereason that H2, for example, could give an indication of a locked boltbefore the bolt had actually locked. The fact that H1 and H4 are presentobliges the control program in the electronics to actuate the driver sothat the lock “over-locks” (H1) and “over-unlocks” (H4).

By using four Hall elements as described above, it is possible to limitthe time for which the motor and the mechanics are subjected toabnormally high loads in those cases in which the lock bolt binds or hasbecome jammed. If the starting position is H4 (locked lock), forexample, and if the motor must cause the magnet to rotate to Hi (lockunlocked), this means that a 180-degree rotation must be executed. Withonly two Hall elements (H1 and H4), the time normally taken to rotatethe driver through 180 degrees must have elapsed before the controlprogram which controls the motor is able to react to the possibilitythat the lock bolt has become jammed.

By using H2 and H3 instead, it is possible to discover very much earlierwhether the lock bolt has become jammed, quite simply by measuring thetime between, for example, H4 and H3 and between H3 and H2 and betweenH2 and H1. The measured times can then be used to determine whether thelock has become jammed or is simply binding. This is known as inertiasensing.

It is entirely conceivable for sensors other than Hall elements to beused to sense the position of the lock bolt as described above. This maybe done, for example, with the help of optical sensors and/or microswitches. Hall elements nevertheless have the advantage that they areinsensitive to dust and dirt, and that they do not possess a mechanicalfunction. The choice of motor is of no significance for the function, ofcourse, with indirect sensing of the position of the lock bolt. It ispossible, for example, to use a stepping motor, a servomotor or anyother form of electric motor, although a stepping motor possessescertain advantages which the other motors do not have.

All the above-mentioned parts can be positioned inside one and the sameenclosure made of metal.

The design of the enclosure is such that, in addition to being attachedto the two screws of the handle, it also engages with the four fixingscrews of the RFID reader coming from the outside of the door. Thisensures a very stable attachment of the unit. The RFID reader and theunit are thus positioned to either side of the door lock.

The invention is naturally not restricted to the illustrativeembodiments described above and illustrated in the accompanyingdrawings. Modifications are possible, in particular with regard to thenature of the various parts, or by the use of equivalent technology,without departing from the area of protection afforded to the invention,as defined in the Patent Claims.

1. Arrangement (1) for sensing the position of the lock bolt (5) in a lock (2) intended for the door (3) to an apartment, for example, which lock comprises an internal lock handle (4), a lock bolt (5), a driver (13) arranged between a motor (7) and the lock (2) for the transfer of force from the motor (7) to the lock (2) and a number of gear wheels (10-12), characterized in that the arrangement is capable of being connected to an existing lock (2), an electromechanical unit (6), with an integral electrically driven motor (7), which is intended to operate the lock handle (4) by actuation of the motor (7), is capable of being applied to the inside (3A) of the door (3), in conjunction with which there is arranged between the motor (7) and the lock (2) a rotating driver (13) for transferring the force from the motor (7) to the lock (2), in that the aforementioned manually actuated lock handle (4) is attached to the driver (13), in that the lock handle (4) is attached to the free end (13B) of the driver (13), in that the motor (7) is a stepping motor and in that a number of sensors (H1-H4) is attached in conjunction with one of the gear wheels (10-12) for detecting the position of the lock bolt (5).
 2. Arrangement in accordance with Patent claim 1, characterized in that a magnet (51) is attached to one of the gear wheels (10-12), and in that the aforementioned sensors consist of a number of Hall elements (H1-H4) which are attached adjacent to the aforementioned gear wheels (10-12) for detecting the position of the magnet (51).
 3. Arrangement in accordance with claim 1, characterized in that the magnet (51) is attached to the gear wheel (12) which accommodates a part (13A) of a driver (13) executed as a flat rotating shaft in an elongated hole (14).
 4. Arrangement in accordance with claim 1, characterized in that, an electronic unit (8), which is capable of being actuated by an electronic key, is capable of being mounted on the outside (3B) of the door (3), which unit is so arranged as to interact with a magnetic field with a predetermined frequency and by wireless communication between the key and the unit (8), a power supply unit is also provided, a central processor unit is so arranged as to monitor the aforementioned electromechanical unit (6) and an RFID reader contained in the electronic unit (8),
 5. Arrangement in accordance with Patent claim 4, characterized in that the electromechanical unit (6) is accommodated by a bottom plate (40) capable of being attached to the door (3) and with a protective enclosure for the parts that are present thereon.
 6. Arrangement in accordance with Patent claim 5, characterized in that the aforementioned bottom plate (40) and the RFID reader are attached to the door with common fixing screws.
 7. Arrangement in accordance with claim 1, characterized in that the number of sensors are at least two.
 8. Arrangement in accordance with Patent claim 7, characterized in that the number of sensors are four.
 9. Arrangement in accordance with Patent claim 2, characterized in that the Hall elements (H1-H4) are mounted on a circuit board (50). 